16x4−y4 = 24x4−y4 = (2x)4−y4 = ((2x)2)2−(y2)2 Using a2−b2 = (a - b)(a + b) identity = ((2x)2−y2)((2x)2+y2) Using the identity one more time = (2x−y)(2x+y)((2x)2+y2) ∴ (2x−y)(2x+y)(4x2+y2)